Bold font not included (anymore?) in font stylesheet

On my site (https://durfteimproviseren.nl/) I use the Lora font as the regular/content font. However, I noticed that all bold text looked kinda ragged (i.e. as if it has been badly photocopied). Some googling brought me to this page: https://www.smashingmagazine.com/2012/07/avoiding-faux-weights-styles-google-web-fonts/ And because if it, I noticed that in the font stylesheet declaration in the head of all Theme pages, the bold font weight (700) is not included: <link rel='stylesheet' id='parallax-frame-web-font-css' href='//fonts.googleapis.com/css?family=Open+Sans:300,300italic,regular,italic,600,600italic%7cLora:300,300italic,regular,italic,600,600italic&subset=latin' type='text/css' media='all' /> As a result of that, a faux bold is used, which looks ragged. I cannot find a way to force the Parallax theme to include this font weight subset. How can I fix this?